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Re: [RFI] Hum in Bose QC2 headphones

To: Rfi@contesting.com
Subject: Re: [RFI] Hum in Bose QC2 headphones
From: "Gary Smith" <Gary@doctorgary.net>
Reply-to: Gary@doctorgary.net
Date: Thu, 15 Jan 2009 10:00:14 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Ron,

I hadn't thought to do that but it is worth while & I'll check that 
out. It would have to be a wall wart in that everything else here is 
three prong.

Interesting that while running my laptop plugged in to its PS I have 
the same problem. I just disconnected the laptop and the hum goes 
away.

Same with my Sansa MP3 player, it works perfectly with these QC2 
headphones. However I just now connected the Sansa to the USB charger 
and with that the hum is back.

The connector in the headphone is a custom one designed to mould 
seamlessly with it's ajacent insertion surface; I'll have to see if 
Radio Shack has a straight stereo cable that will fit in there, It's 
seeming more & more like it's either a design defect or the wire is 
in some way defective. There is a switch on the headphone end of the 
plug which changes the Z to match the input source and changing the 
setting does nothing. Maybe the issue is in that mechanism...

The real issue for me is the quality of reception with these noise 
cancelling headsets is the best I have ever heard, It's like 
listening through the worlds best headphones in relative silence. 
They're to this point perfect for copy and far better than other 
headsets I have including a nice studio set that is arguably more 
accurate in reproduction quality but do not cancel the outside noise 
anywhere close to these. Given the two options, the QC2 is miles 
ahead except for that %^&*()@ hum.

Last night I gave in & ran a connector from the computer chassis to 
my ankle and that killed the buzz 100% & worked the TS7C on 160M He 
was faint here but with the quality of the K3's diversity receive & 
those headsets, he was perfect Q5 as in a true 519.

Gary
KA1J

> Is it worth checking to see of there are any two prong plugs on the 120V
> circuit and plugging them in 180 the other way (including wall warts)??
> 
> 73 es God Bless de KK1L...Ron Rossi (kk1l@arrl.net) <><
> QTH: Jericho, Vermont
> My page: http://home.comcast.net/~kk1l
> 
> WX5L wrote:
> > Gary,
> > 
> > At this point you need to check that the ground(s) in the headphone jack 
> > are still secure to the chassis of the rig. It seems that the result of a 
> > poor ground from the jack to the chassis could be the culprit. Open the rig 
> > and inspect the grounds. There may be seperate ground paths for tip and 
> > ring(stereo). The ground for one side may have been interrupted.
> > 
> > Randy
> > WX5L
> > --
> > 
> > 
> > WX5L
> > Thibodaux, LA
> > 
> > ---- Gary Smith <wa6fgi@sbcglobal.net> wrote: 
> >> >From the other Gary Smith.
> >> Are those Bose headphones *really* worth that kind of money?  Have seen 
> >> their ads, just curious if they are that much better in service on a HF 
> >> rig than other brands.
> >> 73,
> >> Gary...wa6fgi
> >>
> >>   ----- Original Message ----- 
> >>   From: Gary Smith 
> >>   To: Rfi@contesting.com 
> >>   Sent: Wednesday, January 14, 2009 6:32 AM
> >>   Subject: Re: [RFI] Hum in Bose QC2 headphones
> >>
> >>
> >>   > Are you certain that both ends of the cable are plugged 
> >>   > in securely? I've heard the symptoms you described when
> >>   > the plug on the headphone wasn't fully seated. Please
> >>   > let us know what you find.
> >>   > 
> >>   > 73
> >>   > 
> >>   > -Kirk  K4RO
> >>
> >>   Hi Kirk,
> >>
> >>   Indeed they are all the way in on both ends & that pesky hum remains. 
> >>   While assuring they are seated well I tried something, which was to 
> >>   have the headphones on and the stereo plug unplugged at the distal 
> >>   end.
> >>
> >>   When not connected there was no hum but when I touched the bare end 
> >>   of the plug to the equipment ground the right sided hum showed up. 
> >>   Nothing surprising here but the same hum showed up regardless of 
> >>   which terminal was touched to ground be it tip, ring or ground.
> >>
> >>   Interestingly if I touch the bare connector with my fingers, there is 
> >>   no hum whatsoever.
> >>
> >>   The plot sickens
> >>
> >>   Gary
> >>   KA1J
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